A bell curve is a graphical representation showing the range of performance that one can expect of a person, group, or object. It has an approximately normal distribution that resembles the shape of a bell. The top of the bell curve shows the mean and median values. Below are the low tier values considered sub-standard performance and, therefore, unacceptable.
The mean (average) and median (middle) are plotted on the x-axis, while the variables are plotted on the y-axis. Essentially, it takes a data set and plans it in order from best to worst performance, regardless of how many people are in a group. It gives an accurate representation of where someone would fall within a specific range of individuals.
Bell curves are normal distributions and are essential to identify financial and economic trends. In the HR domain, they are used to measure employee performance and for performance appraisal. The peak of a bell curve depicts the mean, median, and mode of a certain set of data.
The Bell Curve Rule implies that 68% of all distribution will be within one standard deviation from the mean (68%), 95% of all distribution will be within two standard deviations from the mean, and 99.7% will be within all distribution three deviations.
A Bell curve is both good and bad. It is beneficial for large to huge companies since they have a lot of data to derive insight from, whereas it is not very helpful for a small company with about 300 or fewer employees. This is because small firms with less data cannot do the curve properly, and the results are mostly skewed.
The advantages of the bell curve are:
1. The employee’s suitability for a particular job position can be identified using the bell curve along with their performance data.
2. Training needs for each employee can be identified using the bell curve along with their competencies.
3. Regular assessment of each employee will ensure that you provide the appropriate lessons and guidance to get better results no matter what the graph shows.
1. The bell curve scales are extremely inflexible and poorly fit smaller-sized companies.
2. With the bell curve scales, companies do not get an opportunity to measure the performance of their employees on an individual basis.
3. There is also no space for growth and other beneficial opportunities.
1. The bell curve is the most widely used method for grading data distribution.
2. It is simple to implement and ensures fairness in performance appraisals.
3. Although the effects of this grading method can be destructive to employee morale.
4. It exists because it is effective and easy to use.